The Himalayan Cryosphere: Why It Matters

Stretching 2,400 km across six nations, the Himalayas form the world’s largest reservoir of ice and snow outside the poles, often called the Third Pole. This frozen system is the primary freshwater source for over 1.3 billion people, and underpins food production, drinking water, hydropower and ecosystem stability for nearly 3 billion across Asia.

But the region is warming at an alarming pace. Average temperatures across the Himalayas have already risen by 1.5°C above pre-industrial levels similar to the Arctic and Antarctic Peninsula. Measuring these changes is challenging: the extreme topography makes each glacier unique, and many areas remain difficult to observe, even with satellites. Yet despite these complexities, the overall trend is unmistakable: the Himalayan cryosphere is in rapid decline. Most glaciers across the region are retreating, snow cover is decreasing, and the eastern Himalayas have seen some of the most dramatic losses, with mean ice thickness dropping by nearly 11 metres in just two decades.

The cost of losing glaciers

Glaciers shape some of the planet’s most iconic landscapes. They carry deep cultural significance for mountain peoples and feature prominently in local spiritual traditions. They also support national and local economies through tourism, mountaineering and adventure travel.

But their most critical role is invisible: regulating freshwater for billions. Glaciers act as natural reservoirs, releasing meltwater when rainfall is scarce. Their loss is therefore not just an environmental tragedy — it is a profound humanitarian and economic threat.

Globally, glaciers (excluding Greenland and Antarctica) are now losing 266 billion tonnes of ice each year. Their melt contributed about 21% of global sea-level rise between 2000 and 2019 (Hugonnet et al, Nature, 2021) accelerating oceanic changes and threatening low-lying regions. The impacts are already being felt: in the UK alone, over 100,000 properties may face coastal erosion by the 2080s, and protecting London could cost more than £20 billion by 2070.

How bad is it?

Worldwide, glaciers separate from the large Antarctic and Greenland ice sheets now lose a total of 266 billion tonnes of ice every year. In the UK alone, by the 2080s, over 100,000 properties may be at risk from coastal erosion, and estimates of sea level rise by 2100 are 0.8 to 2.6 m under current climate policies costing £500 million per year, Protecting London, required by 2070 CE, could cost more than £20 billion.

What can we do to preserve glaciers?

Once glaciers pass certain thresholds, their loss becomes irreversible on human timescales. None of the proposed geoengineering ideas for “saving” glaciers have been tested at scale, and many could cause more harm than good.

The only proven solution is also the most straightforward: rapid and deep cuts to greenhouse gas emissions. Reaching global net zero is not an abstract ambition; it is the only pathway that gives the world’s glaciers and the billions of people who depend on them a chance.

Protecting the Himalayan cryosphere is not only about safeguarding mountain communities. It is about protecting global water security, food systems, coastal cities, and climate stability for generations to come.